The following patents are incorporated herein by reference in entirety: U.S. Pat. No. 8,439,800 discloses a shift control system for a marine drive, which applies partial clutch engagement pressure upon initial shifting from forward to reverse to prevent stalling of the engine otherwise caused by applying full clutch engagement pressure upon shifting from forward to reverse.
U.S. Pat. No. 7,997,398 discloses a marine transmission having a cylindrical spool valve that is disposed within the gearcase of the transmission and having a movable portion that is axially movable in a vertical direction to select forward, neutral, and reverse gear positions of the transmission. A piston assembly provides a primary piston and two auxiliary pistons which cooperate with each other to provide appropriate hydraulic forces which move a dog clutch into engagement with forward or reverse gears or toward a location in non-engagement with neither the forward nor reverse gears. The spool valve is generally cylindrical and disposed within a narrow column portion of the gearcase of a marine propulsion system.
U.S. Pat. No. 7,544,110 discloses an actuator for a marine transmission that uses four cavities of preselected size to provide four potential forces resulting from pressurized hydraulic fluid within those cavities. The effective areas of surfaces acted upon by the hydraulic pressure are selected in order to provide increased force to move the actuator toward a neutral position from either a forward or reverse gear position. Also, the relative magnitudes of these effective areas are also selected to provide a quicker movement into gear than out of gear, given a similar differential magnitude of pressures within the cavities.
U.S. Pat. No. 7,297,036 discloses a marine transmission wherein trailing faces of each of a plurality of gear projections extend axially from a forward gear are provided with a rake angle. This rake angle of each trailing face cooperates with an associated surface of each of a plurality of clutch projections to retain a dog clutch in an axial position relative to the forward gear even during periods when a marine vessel is rapidly decelerating and, as a result, the dog clutch moves into driving relation with the forward gear.
U.S. Pat. No. 7,291,048 discloses an actuator of a marine propulsion transmission that is attached to a movable clutch member through the use of a coupler which comprises a generally spherical member formed as a portion of the actuator and a chuck device formed as part of the clutch member. The generally spherical member, or alternatively shaped component, is received by the chuck device and retained therein. The components are configured to allow relative rotation between the actuator and the clutch member while causing them to move axially in synchrony with each other.
U.S. Pat. No. 6,544,083 discloses a gear shift mechanism in which a cam structure comprises a protrusion that is shaped to extend into a channel formed in a cam follower structure. The cam follower structure can be provided with first and second channels that allow the protrusion of the cam to be extended into either which accommodates both port and starboard shifting mechanisms. The cam surface formed on the protrusion of the cam moves in contact with a selected cam follower surface formed in the selected one of two alternative channels to cause the cam follower to move axially and to cause a clutch member to engage with either a first or second drive gear.
U.S. Pat. No. 4,223,773 discloses a clutch apparatus for a marine drive lower gearcase, which includes a propeller shaft rotatably mounted in a gearcase housing. A drive gear for both forward and reverse is positioned in the housing coaxial with the propeller shaft and a clutch member is rotatably fixed on the propeller shaft and movable axially into drive engagement with the drive gear. Clutch engaging elements are provided on opposed portions of the drive gears and the clutch member. Shift means utilizing a positive acting cam means positively move the clutch member into and out of engagement from the drive gears. The shift means also include a releasable latch means to positively maintain the shift means in the engaged position and a preloading means between the shift means and the clutch member to snap the clutch member into engagement.
U.S. Pat. No. 3,943,790 discloses a marine outboard gear assembly, usable in an outboard motor or an inboard-outboard drive, and featuring (a) constant drive of the meshing gears which transfer power to the propeller-shaft axis, and (b) selective spring-clutching direct to the propeller shaft, thereby (c) utilizing the meshing gears for lubricant circulation as long as the engine is operating and whether or not the clutch is engaged and (d) reducing to an absolute minimum the drag and inertial effects operative upon the propeller shaft when the boat is moving in the declutched condition, i.e., propeller windmilling. Also featured is a particular subassembly of gear and clutch parts on the propeller shaft whereby desired axial clearance can be readily pre-adjusted and selected, prior to assembly to the gearcase.